I found a St. Dupont Ligne 2 in Brushed Palladium that passed all the "how to spot a fake" requirements on this board. (Lettering on serial is hand done, yellow paint under cap, weighs 115 grams, iodine test = positive for palladium)

I also sent pictures to an engineer at S.T. Dupont corporate and it passed authenticity for him. So I'm pretty sure its legit.

What's weird is that it looks just slightly different from the current model (No. 016404). Also, while purple velvet interior, black exterior, warranty card, and booklet

they make a ton of variations over the years, its probably just an older model. also it's possible that the box is a newer box than it would have came - no guarantee that someone didn't swap the box out, sellers do all sorts of funny things sometimes.